A protocol is a set of procedures for communications over a network. In the Internet Protocol (IP), information such as the IP addresses of the sender (source) and the receiver (destination) of the data packets is placed in a “header” positioned in front of the data. In Internet Protocol version 6 (IPv6), which is an improved version of IPv4, a “flow label” field is included in the header. The flow label field plus the source and destination IP addresses can uniquely identify the data packets constituting a media flow in IPv6. With such an identifier for a media flow, packets can be differentiated and processed accordingly.
Among the problems that exist in the transmission of media streams over a digital network is how to allow routers to prioritize routing of certain media flows over other media flows, and the selection of physical resources (e.g., output interface) for a particular media flow. Solving these problems depends upon properly monitoring and attending to a media flow, which, in turn, requires the establishment of a flow state in IPv6. Unfortunately, establishing a flow state at the middle nodes in the transmission path is problematic.